Method of making a muffler



Sept. 27, 1966 P. G. ANDREWS METHOD OF MAKING A MUFFLER Original FiledMay 11, 1962 United States Patent 3,274,678 METHOD OF MAKING A MUFFLERPeter G. Andrews, Kitchener, ()ntario, Canada, asslgnor to WalkerManufacturing Company, a corporation of Delaware Original applicationMay 11, 1962, Ser. No. 193,927, now Patent No. 3,159,239. Divided andthis application May 25, 1964, Ser. No. 370,021

1 Claim. (Cl. 29-471.1)

This invention relates generally to sound deadening devices andparticularly concerns improvements in muffiers for internal combustionengines and the like. This application is a divisional application ofSerial No. 193,927, filed May 11, 1962, now U.S. Patent No. 3,159,239.

In manufacturing mufflers for differently shaped and sized vehicleshaving differently shaped and sized exhaust system piping, it isnecessary to construct the end fittings of the mufiier shells so thatthey coincide in size and direction to the exhaust system piping intowhich the mufiler is to be connected. This necesssity arises from thefact that the end fittings project into or over the ends of the exhaustsystem piping in a telescoping manner and, therefore, the fittings mustbe axially aligned with the piping as Well as being the proper size. Itfollows, therefore, that many variations in the size and direction ofthese end fittings must be provided. On low production mufflers the costof tooling and shortrun setups to provide various end fitting alignmentscan be very high per muffier and can result in abnormally high mufflerprices.

It is, therefore, an important object of the present invention toprovide an improved low cost muffler shell and end fitting arrangementwhich reduces the cost of manufacturing mufflers having variable endfitting configurations and sizes.

Another object is to minimize or eliminate the need for alteration ofmufller manufacturing facilities for the manufacture of mufllers havingdifferently directed end fittings.

Another object is to provide an improved joint between the open ends ofa muffler shell and the end fittings therefor, which joint can functionas an adapter for adapting various size mulfler shells to various sizeand directed end fittings.

A further and more specific object is to provide a three-piece mufilershell construction readily adapted for manufacture for a variety ofsizes and shapes of vehicle exhaust systems.

Further objects, advantages and novel features of the invention willbecome apparent from the following description, claim, and drawingswherein:

FIGURE 1 is a longitudinal sectional view of a preferred form of thethree-piece mufiler shell; and

FIG. 2 is a right hand end view of the shell of FIG. 1.

Referring to the drawings, a mufiier shell generally designatedcomprises a cylindrical body 12 and a pair of tubular end fittings 14and 16. The opposite ends of body portion 12 are given arcnatecurvatures 18 and 20. These are preferably of the same radius ofcurvature, but, may be formed on different radii should such bedesirable. Surfaces 18 and 20 each preferably comprise segments ofhemisphere for a purpose hereinafter described. The body ends areapertured at 22 and 24. The end fittings 14 and 16 are flared at 26 and28,

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respectively; and the outer portions of these flares are formed witharcuate hemispherical segments 30 and 32 respectively havingcircumferences concentric with arouate surfaces 18 and 20, respectively.This construction allows fittings 14 and 16 to be respectivelypositioned on the outside of surfaces 18 and 20 either in alignment withor angularly to the longitudinal axis 34 of the mufller body whileforming gas tight seals at the juncture of the surface pairs 18, 30 and20, 32. The angular direction is illustrated by end fitting 16 whoselongitudinal axis '36 is offset several degrees from axis 34 of the body:12.

The arcuate end surfaces 18 and 20 of the body 12 are formed from astraight tube as indicated by the phantom lines 3 8 and '40 in FIG. 1 byrolling or swaging or other suitable metal forming operation. Similarly,the fiared portions 26 and 28, and the arcuate surfaces 30 and '32respectively of end fittings .1 4 and 16 are formed from straight tubes42 and 44 indicated by the phantom lines also by rolling, swaging, orother suitable metal forming operation.

Any suitable internal sound attenuating structure 54 inside of themufiler may be used. Structure in ac cordance with a copen-ding U.S.application of R. A. Heath, Serial No. 115,991, now Patent No.3,141,518, and assigned to the assignee hereof is preferable.

End fittings 14 and 16 are secured to body 12 after the proper angulardirection of these fittings with respect to the exhaust system pipinghas been determined and the lfittings adjusted on body 12. Thissecurement may be made by various means but is preferably an annularweld along the peripheral edges of the arcuate surfaces of the fittingsas indicated at 4 5.

It is seen that regardless of the angular position of the end fittingson body 12 the bores or cavities 46 of the fittings thereof are in wideopen communication with the open ends 22 and 24 of the body. Thesurfaces 30 and 32 may be made of larger area than shown to cover moreof surfaces 18 and .20 respectively to provide better seals and to allowgreater angular offset than is illustrated by fitting 1'6.

Modifications may be made without departing from the spirit and scope ofthe invention.

I claim:

The method of making a mufller for automotive exhaust systems, saidmufiler having an outer shell and conduit connecting fittings atopposite ends which comprises inserting silencing means inside saidshell, indenting the opposite ends of a tubular outer shell to formspherical surfaces, enlarging the ends of tubular end fittings to formspherical surfaces thereon, positioning the spherical surfaces of thefittings on the spherical surfaces at the ends of the shell andadjusting said fittings so that the axes thereof make the desired angleswith the axis of the shell, and welding the spherical surfaces of thefittings to the spherical surfaces of the shell.

References Cited by the Examiner UNITED STATES PATENTS 1,608,245 1 1/ 1926 Schwager 1816 1 X 1,695,3 12/ 1928 Heather.

1,838,249 12/19 31 Brown 29-482 X 2,200,162 5/1940 De Vulitch 29-479JOHN F. CAMPBELL, Primary Examiner.

